1. Field of the Invention
This invention lies in the field of fluid dispensing devices. More particularly, it concerns devices for dispensing fluids in which pressurizing gas is not required, and the pressure which drives the fluid through the outlet valve results from the elasticity of a tubular member or sack into which the fluid is inserted under pressure.
2. Description of the Prior Art
Pressurized containers for dispensing fluids have become very popular for handling many types of fluids in large and small sizes. In the prior art, most of the dispensers have utilized a propellant gas for pressurizing the fluid. Considerable difficulty has been experienced in the construction of the units, and in the handling and disposal of units, particularly after most of the fluid has been dispensed. Furthermore, the cost of the propellant gas is a considerable part of the cost of the device and, of course, this is wasted, since it simply serves to drive the fluid through the valve and into a spray.
Furthermore, the chemical nature of the propellant gas that has been found most useful in recent years is now believed to be damaging to the environment. Attempts are being made to design dispensing systems which do not require such propellant gases.